Addition agents and mineral oil lubricant compositions containing the same



Patented July 15, 1952 2,008,800 ADDITION AGENTS'AND MINERAL OIL LU- BRICANT COMPOSITIONS CONTAINING THE SAME.

Herschel G. Smith, Wallingford, in Tro L. Cantrell, Lansdowne, 2a., minors to Gulf Oil Corporation, Pittsburgh, Pa a corporation of Pennsylvania No Drawing. Application June '1, 1948. Serial No. 31,593

Claims. (01. 252-483) This invention relates to addition agents and mineral oil lubricant compositions containing the same and, more particularly, it is concerned with improvement agents which confer improved anti-oxidant, corrosion-inhibiting, detergency and pressure-carrying properties on mineral oil lubricants.

It is recognized in the art that mineral oil lubricants are readily oxidized under service conditions thereby reducing the service life of internal combustion engines and steam turbines. A concomitant effect is corrosion of bearing surfaces.- These problems become particularly acute when a highly refined paraillnic base mineral oil is employed as the lubricant.

In the 'lubrication of internal combustion engines of all types, particularly when severe operating conditions are encountered, mineral lubricating oils frequently prove unsatisfactory because they tend to deposit varnish, gum and sludge on the engine surfaces, such as the cylinder walls, pistons and rings, and also to induce corrosion of bearing materials thereby causing failure of the engine. These problems have become increasingly serious because of the trend toward higher eiilciency or higher power output per unit weight of engine, which results in conditions tending to accelerate the deteriorating influences on the mineral oil lubricant. The formation of so-called varnishes and sludges on engine surfaces is a result of oxidation effects on the lubricating oils. The presence of gums, varnishes and sludges is detrimental for many reasons. These substances tend to increase ring sticking and accelerate the formation of further deposits on piston surfaces and in flxed parts of the combustion chamber. The sludges formed in the crankcase of the engine increase the rate of corrosion of bearing surfaces, especially of searing alloys of the types now in use. p

In steam turbines, the corrosion problem is particularly acute because of the presence of water in the mineral oil lubricant and in addition to hearing corrosion, rusting may also be encountered.

It is an object of this invention, therefore to prepare an improvement agent which will obviatethe oxidation and corrosion difilculties encountered in the use of mineral oil lubricants.

It is a further object of this invention to provide improved mineral oil lubricant compositions which are stable in storage and use and in which oxidation and corrosion effects are materially inhibited.

It is also an object of this invention to provide mineral oil lubricant compositions having excellent detergency and pressure-carrying properties.

In our copending application Serial No. 718,902, iiled December 21, ll", there is disclosed and claimed an addition agent for mineral oil lubricants which confers excellent antioxidant, corrosion-inhibiting and pressure-carrying properties on mineral oil lubricants. Such improvement agent is prepared by'heating an essentially parafllnic base lubricating oil with aluminum chloride, removing aluminum chloride from the reaction product and reacting laid product with phosphorus pentasuiilde at an elevated temperature to incorporate phosphorus and sulfur therein.

In our copending application Serial No. 736,618, filed March 24', 1947, now U. S. Patent No. 2,456,336, there is disclosed and claimed an improvement agent for mineral oil lubricants which is prepared by heating an essentially parafllnic base lubricating oil with phosphorus pentasuliide in the presence of a surface active silica-containing solid catalyst. It is shown in. that application that when phosphorus pentasulflde is reacted with an essentially paramnic base lubricating oil in the presence of a surface active silica-containing solid catalyst, the prior aluminum chloride treatment of the lubricating oil as disclosed in our application Serial No. 718,902 may be omitted. It is also shown in our latter filed application that when the prior aluminum chloride treatment of the parafllnic base lubricating oil is combined with reaction of the aluminum chloride treated product with phosphorus pentasulilde'in the presence of a surface active silica-oontaining catalyst, lighter colored products are obtained.

The objects of the present invention are accomplished by providing improvement agents for mineral oil lubricants by reacting an essentially paraiiinic base lubricating oil or the aluminum chloride treated product thereof with' phosphorus pentasulilde, through the use of any of the methods disclosed in our copending applications Serial Nos. 718,902 and 736.618, now U. 5. Patent No. 2,456,336, and with a monohydric alkylated phenol having at least 4, carbon atoms in an alkyl group. Such improvement agents,

, as well as the mineral oil lubricant compositions containing them, are believed to be novel and are considered parts of our invention.

The present invention may be regarded as an improvement over the inventions disclosed in our above-identified copending applications. While the addition agents disclosed therein confer excellent antioxidant, corrosion inhibiting and pressure-carrying properties on mineral oil lubricants, they sometimes fail to pass the well known Copper Strip Test (Method 530.31. Federal Specification W-L-79lc, May '12, 1945, page 259) thus indicating the presence of elementary sulfur or the so-called .corrosive" sulfur. While we do not wish to be bound by any theory as to the exact nature of our phosphorus pentasulfide reaction products, it is our present belief that either elementary sulfur or incompletely bound sulfur or both are formed in the reaction. In accordance with the present invenftion, such elementary or incompletely bound sulfur is "neutralized" or "accepted" by combination with the alkylated phenol added in vthe preparation of the phosphorus pentasulfide reaction product.

It is still necessary for thepurposes of the present invention to employ an essentially parafviinic base lubricating oil as the initial material,-

because other hydrocarbon materials produce a black, sludge-like, difllcultly soluble product'regardless of whether the prior aluminum chloride treatment or reaction in the presence of a surface active silica-containing solid catalyst are employed. The reasons for the advantageous ef-- fects of the prior aluminum chloride treatment or of thesurface active silica-containing solid catalyst on the reaction. when an essentially parafilnic base lubricating oil is employed are not fully understood. However, the use ofat least oneof these methods is essential for the practice of our invention since, if the prior aluminum chloride treatment or the use of a surface active silica-containing catalyst is omitted, the advantageous results of our invention are not obtained.

in order to obtain the results of our invention,

therefore, it is necessary (1) to employ an essentially paraflinic base lubricating oil, and (2) to conduct the reaction. of the oil and alkylated phenol with phosphoruspentasulfide only after aluminum chloride has been reacted with the oil and/or the reaction with phosphoruspentasullubricating oil with aluminum chloride, such treatment is accomplished as described in our copending application, Serial No. 718,902. Briefly, such treatment comprises heating the essentially paramnic base lubricating oil with from 1 to 20 per cent by weight of anhydrous aluminum chloride at a temperature of from 150 to 300 F. while the mixture is vigorously agitated. The time of treatment may vary in accordance with the amount of aluminum chloride used and the temperature of treatment, longer times being required with less aluminum chloride and lower temperatures. In general. the treatment will be completed after four or five hours. After the treatment is completed, agitation is stopped and a sludge containing most of the aluminum chloride settles out'from the main'body of the oil and is drawn oif. The supernatant body of the treated oil may contain further quantities of aluminum chloride finely dispersed therethrough,

. and in order to insure the removal of all aluminum chloride from the treated oil, agitation with an adsorbent clay followed by filtration may be employed. At the higher temperatures of treatment with aluminum chloride some conversion of the paraflinic base oil to lower boiling products may take place. Although such conversoin is slight,' the product may be topped if desired. that is, distilled to remove the lower boiling products 4 overhead and .to'recover, as a residue the bulk of the aluminum chloride treated oil having a minimuminitial boiling point in-the range 490' to alkylated phenol and phosphorus pentasulfide.

This may be accomplished either by reacting with phosphorus pentasulfide per se, as disclosed in our copending application Serial No. 718,902, or in the presence of a surface active silica-containing solid catalyst as disclosed in our ccpending application'serial No. 736,618, now U. 8. Patent If it is desired to react the aluminum chloride treated oil and the alkylated phenol with phosphorus pentasulfide per se, this reaction is accomplished by adding from 2 to per cent by weight of Pass preferably 5 to 10 per cent, and heating with agitation at a minimum reaction temperature of 450 F. and a maximum reaction temperature below the temperature where cracking of the oil begins. Hydrogen sulfide is evolved and when the evolution of hydrogen sulfide has nearly ceased, the temperature of the reaction mixture may be increased within the maximum temperature disclosed above, say to about 500 F. for the completion of the reaction.

If desired, the aluminum chloride treated paraffinic base lubricating oil and the alkylated phenol may be reacted with phosphorus pentasulfide in the presence of a surface active silica-containing catalyst; or, the prior aluminum chloride treatment may be omitted and the essentially parafilnic base lubricating oil and alkylated phenol may be reacted with phosphorus pentasulfide in the 1 presence of a surface active silica-containing solid catalyst. The reaction of the essentially parabflnic base lubricating oil and alkylated phenol, whether or not pretreated with aluminum chloride, with phosphorus pentasulfide in the presence of a surface active silica-containingsolid catalyst is accomplished by adding 2 to 20 per cent by weight of P285, preferably from 5 to 10 per cent, to the essentially paraflinic base lubricating oil and heating with agitation at a temperature in the range from 300 F. to a maximum temperature below the temperature where cracking of the oil, that is. pyrolytic decomposition of the oil.

begins. Generally the minimum crackingv tem-' perature of the oil varies between 490 to 53091 9., depending upon the particular oil used. The surface-active silica-containing solid catalyst is employed in amounts of from 2 to 25 'per cent by weight of the oil charged and preferably in an amount of 10 per cent by weight. larger amountsthan 10 per cent are ordinarily not necessary, but larger amounts will produce a product having a lighter color. During the course of the reactionhydrogen sulfide is evolved and the phosphorus and sulfur become incorporated in the reaction product. When the evolution of hydrogensulfide has nearly ceased, the temperature of the reaction mixture may be increased within the maximum temperature mentioned above, say to about 500 for completion of the reaction. The

mixture is then filtered to remove'the catalyst.

The surface active silica-containing solid catalysts may comprise activated clays, silica-aluminacracking catalysts and the like. Thus. activated clays, that is natural clays such as bentonite. smectite, floridin, fullers earth and the like which have been treated with acid, such as are described in U. 8. Patent No. 1. .165. for example. may be butyl phenol.

2,283,173, may also be employed. Activated silica v gel is also suitable. As may be seen, the term surface active-silica-containing solid catalyst comprises a wide variety of materials. the predominant characteristic of which is the presence of silica in a surface active, that is, activated form.

In accordance with the present invention, a monohydric alkylated phenol having at least 4 carbon atoms in an alkyl group is admixed with the essentially parafiinic base lubricating oil and the mixture reacted with phosphorus pentasulfide as disclosed hereinabove; or the alkyiated phenol may be added to the mixture of the phosphorus pentasulfide and the essentially parafllnic base lubricating oil during the reaction after the evolution of hydrogen sulfide has substantially ceased, but prior to completion of the reaction. The alkylated phenol is ordinarily added in proportions ranging from 5 to 50 per cent by weight of the parafilnic base lubricating oil, sufllcient to remove free or corrosive" sulfur in the phosphorus pentasulfide reaction product.

Among the monohydric alkylated phenols having at least 4 carbon atoms in an alkyl group, there are included the following:

4-tertiary-butyl phenol 2-tertiary-butyl, 4-sec-butyl phenol 2,4-di-tertiary-butyl phenol 2,6-di-tertiary-butyl phenol 2.4,6 tri-tertiary-butyl phenol 2,6-di-tertlary-butyl, 4-sec-butyl phenol 2,6-di-tertiary-butyl, 4-methy1 phenol 4,6-di-tertiary-butyl, 2-methyl phenol 2-tertiary-butyl-4,6-dimethyl phenol 2-tertiary-amyl-4,6-dimethyl phenol 2,4,8-tri-tertiary-amyl phenol 2-tertiary-butyl-4,6-di-tertiary-amyl phenol Diisobutyl phenol Triisobutyl phenol The preferred alkylated phenols are the monohydric alkylated phenols having from 4 to 12 carbon atoms in a branched chain alkyl group. These are conveniently prepared by alkylating a simple phenol, such as phenol itself, the cresols and xylenols, with a suitable olefin in the presence of concentrated sulfuric acid as a catalyst. See, for example, U. S. Patent 2,149,759, patented March 7, 1939. Oleflns such as butene-l, isobutylene, the a'mylenes (or mixtures of the preceding in reflnery gas) diisobutylene and trl-isobutylene may be employed. It is preferred to conduct the alkylation of phenol with di-isobutylene since the resulting octyl (diisobutyl) phenol is primarily para-(alpha,alpha, gamma, gamma) tetramethyl The phenols may be employed either singly or as a mixture, and for the purposes of this invention any of the above phenols or a combination of them may be employed.

The following examples illustrate the preparation of our new improvement agents.

Example 1 After about one hour at this temperature, the evolution or hydrogen sulfide had substantially subsided. The temperature of the reaction mass was then raised to 520 F., and the mass agitated at this temperature for about 3 hours. The mixture was then cooled. The product had the following properties:

Gravity, "API 16.5 Viscosity, SUV, 210 F 68.0 Sulfur B, percent 5.1 Phosphorus, percent 2.5 Neutralization No 10.0

Example II Forty-five (45) parts by weight of a well refined parafllnic base motor oil stock were treated with 10 parts by weight of Past in the presence of 10 per cent by weight of an activated clay catalyst at a temperature of 480 F. for 4 hours. Then 45 parts by weight of octyl phenol were added and themixture reacted at 530 F. for 2 hours. The product was then filtered to remove the catalyst. The product had the following properties:

Gravity, APT 17.0 Viscosity, SUV, 210 F 71.0 Sulfur B, percent s 4.8 Phosphorus, percent 2.4 Neutralization No 9.0

Example III temperature for 2 hours. The product was filtered to remove the clay catalyst, and had th a following properties:

Gravity, API 18.5 Viscosity, SUV, 210 F 73.5 Sulfur, B, percent 4.9 Phosphorus, percent 2.45 Neutralization No 8.5

The reaction products obtained in accordance with the preceding examples are excellent improvement agents for mineral oil lubricant compositions. They are light colored and readily soluble in all types of mineral oils, that is paraflinic, naphthenic or mixed base mineral oils and, as a matter of fact, can be blended with mineral oils in proportions as high as 50 per cent by weight or higher. This excellent solubility of our new improvement agents enables the preparation of concentrated solutions. which may then be diluted down to the proportion desired in the flnai mineral oil lubricant composition. As stated, our new improvement agents confer excellent antioxidant, corrosion-inhibiting and pressure-carrying properties on the mineral lubricating oils with which they are incorporated, and'are characterized by a high degree of potency at high temperatures. In addition, these agents are excellent detergents and anti-ring sticking agents when used in heavy duty motor oils. For these purposes, our new improvement agents are generally added to mineral oils in minor amounts. say from 0.1 to 20 per cent by weight of mineral oil, sumcient to confer improved detergent,

pressure-carryins. antioxidant and corrosioninhibiting properties on the mineral lubricating Ix'emple III with 09.5 per cent by weight of a turbine 01! A comparisonoi the br om.

ties of the improved and unimproved lubricants. follows:

l5 Unim 'ro'vsd Turb eqil 'lur lu eOil m: ag i 00.2 f a01- ioo fi'w-u' e00 200 20 Color, NBA 1.6 1.6 Neutrslilbti -No 0.01 0.02 Oxidation an Benin Cm,

sion Test Method 26 Guli:

Duratl0n'of'lest,firs; 48 Oil Bath Tem tum I; 841 347 .Air Rate: 00%;: I p 2,000

grunt! oi" il: 00 800 earin ype -Ag Cir-Rb Cd-Ag Cu-Pb wac :Gram 0.2 0.01 0.03 Copper Strip Fest. Passes. Passes...

Example V I An improved motor oil was prepared by blendin: 1 per cent by weight of the additive of Ex- I lubrloautel had the fololwing properties! An improved E. P. gear lubricant was prepared by adding percent by weight of the additive of Example'III to 85 per cent by weight ofa suitable base stock. The unimproved} and improved.

Unlmproved Iln lubricant Lu ricant Gravit can. m m' Viscosity svv 210' L 101 cu Io Load Lb 10 40+ Almen'lest: I 7

IA"! Load: Lbs... 8 80+ Copper Strip 'Iert.. Passes Passes Example i!!! serlal No'. 736.618, MWU. 8. Patent N0- 2,456,338,

and the-present invention were subjected to the e Motor Service Test, Method 259, Gulf, described in U. 5. Patent 2,342,431. In'each instance 3 parts by weight of the additive were compounded with 97 parts by weight of a highly refined ample Iwithflkper cent by weight of solvent the base lubricant follows:

Unimproved Im raved Lubricant Lu rimnt gmw 5-62, 2&7 1

F; 338 33g Col0r,.N PA 4.25 4.25 Oxidation dz Bearing 00 Test ethod 257, G If.

' Duration of Test: Hrs 48 48 Oil Bath 'lem 34 7 347 antezcc r 2,000 2,000 uantity oi cc I 000 300 caring-Type Cd-Ag Cu-Pb Cd-A Cu-Pb Wt. Change: Grams. 0.05 0.1 7 0.0276 g Per Cent.-... 0.27 0.45 -0. 01 -0.01 Copper Stri Test. i...n. Passes Passes olaelvzilii4 HourEngine Test 1 giggle Cfgditifii will: fails 06 as: g. o e I Fearful 1,210 121 The oxidation and Bearing Corrosion Test. Method. 2157 Gulf referred to in the foregoing examples is conducted as follows: An alloy hearing shellof certain commonly used standard dimensions is submerged in 300 cc. of the oil or oil composition to be tested in-a 400 cc. Pyrex beaker andheated in a thermostatic oil bath to 347 F. Air is then bubbled through the oil in contact with'the bearing shell at a rate of 2000 cc. per hour. At the end of 48 hours thelcss of weight. and condition of the bearing shell are determined. the bearing shell being washed free 'of oil and dried before weighing. when determim ing the effectiveness of. various improvement agents, the usual procedure is to run a blank test simultaneously with the oil composition being tested, employing for that purposev a sample of the untreated oil. In this test it is advantageous to employ commercial, bearing shells. These shells comprise a suitable metal backing faced withthe alloy bearing metal. In this way the actual bearing face is subjected to severe deterioration conditions. By :comparison'ot the re- Lubricant. Lubricant Lubricant 018. N. of B. N. of Present 718,002 730,018 Invention 337' 330 sea 4. 26 4. 25 4. 25 Tarnished 'larnished Passes M suits of such tests with actual service tests, we have found them to be in substantial agreement as to suitability of particular lubricants.

The Chevrolet 36 Hour Engine Test referred to above is an accepted standard test designed to determine the oxidation, bearing corrosion, and detergency characteristics of engine crank case oils designed for use under heavy duty service conditions. In this procedure, the crank case lubricant is evaluated with respect to its stability ,or resistance to oxidation, bearing corrosion and the deposition of contaminants resulting from decomposition and oxidation or other changes that occur in the lubricant in service. The procedure involves the intermittent operation of a special fi-cylinder automotive test engine at constant speed and load for a total of 36 hours subsequent to a run-in period of 8 hours at graduated speeds and loads. Prior to each test a complete set of new piston rings is installed and two new weighed copper-lead test bearings are installed in symmetrical location. Performance of the test oil is Judged by examination of the power section of the engin for deposits and by ascertaining the weight loss of the test bearings. The detergency characteristics are expressed as "Engine Condition Rating" and indicate the freedom from engine deposits expressed in per cent, the larger the per cent (approaching 100 as I v a limit) the cleaner the engine. The amount of hearing corrosion is indicated as Bearing Loss and is expressed in milligrams loss in weight of the standard bearing.

As shown in the abov examples, the addition of our new improvement agents to mineral oil lubricant compositions confers excellent detergency, pressure-carrying, antioxidant and corrosion-inhibiting properties. At the same time the compositions so obtained are stable in storage and use and have a color which is substantially unaflected by the addition of the improvement agent. The lubricants obtained pass the Copper Strip Test.

While we have'shown in the examples the preparation of compounded lubricating oils, our invention is not limited thereto but comprises all -mineral oil lubricant compositions containing our new improvement agents, such as greases and the like. Furthermore, conventional addition agents such as viscosity index improvers, pour point depressants, anti-foam agents and the like may be added without departing from the spirit of the invention.

We claim:

1. The process of preparing an improvement agent for mineral oil lubricants which comprises 2. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially paraflinic base lubricating oil with anhydrous aluminum chloride at a temperature of from 150 to 300 F., removing aluminum chloride from the reaction product, and reacting said product and from 5 to 50 per cent by weight of a monohydric alkylated phenol hav- 10 ing at least 4 carbon atoms in an alkyl group with phosphorus pentasulflde at a temperature of from 450 F. to a maximum temperature below the minimum cracking temper ture of said product to incorporate phosphorus and sulfur therein.

3. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially paraiiinic base lubricating oil with from 1 to 20 per cent by weight of aluminum chloride at a temperature of from to 300 F., removing aluminum chloride from the reaction product, and reacting said product and from 5 to 50 per cent by weight of a monohydric alkylated phenol having at least 4 carbon atoms in an alkyl group with from 2 to 20 per cent by weight ofv phosphorus pentasulfide at a temperature .of from 450 F. to a maximum temperature below the minimum cracking temperature of said product to incorporate phosphorus and sulfur therein.

4. The process of claimg3, wherein the product is dissolved in a mineral lubricating oil.

5-.ifThe process of claim 3, wherein the alkylated phenol is a monohydric alkylated phenol having from 4 to 12 carbon atoms in a branched chain alkyl group.

6. The process of claim 3, wherein the alkylated phenol is para-tetramethylbutyl phenol.

7. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially parafiinic base lubricating oil with phosphorus pentasulfide in the presence of a surface active silica-containing solid catalyst and from 5 to 50 per cent by weight of a monohydric alkylated phenol having at least 4 carbon atoms in an alkyl group at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said lubricating oil to incorporate phosphorus and sulfur therein. 1

8. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially paramnic base lubricating oil with from 2 to 20 per cent by weight of phosphorus pentasulflde in the presence of from 2 to 25 per cent by weight of a surface active silicacontaining solid catalyst and from 5 to 50 per cent by weight of a monohydric alkylated phenol ha wing at least 4 carbon atoms in an alkyl group at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said lubricating oil to incorporate phosphorus and sulfur therein.

9. The process of claim 8, wherein the alkylated phenol is a monohydric alkylated phenol having from 4 to 12 carbon atoms in a branched chain alkyl group.

10. The process of claim 9. wherein the alkylated phenol is para-tetramethylbutyl phenol.

11. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially paramnic base lubricating oil with from 1 to 20 per cent by weight of anhydrous aluminum chloride at a temperature of from 150 to 300 F., removing aluminum chloride from the reaction product, heatingsaid product with from 2 to 20 per cent by weight of phosphorus pentasulflde in the presence of a surface active silica-containing solid catalyst and from 5 to 50 per cent by weight of a monohydric alkylated phenol having at least 4 carbon atoms in an alkyl group at a temperature of from 300 F. to a maximum temperature below. the minimum cracking temperature of the aluminum chloride treated oil to incorporate phosphorus and sulfur therein.

ollimi.

l2.-The product obtained by the process orclaim 1; 18. The product obtained by the process oi claim 4.

obtained by the process 01 14. product and corrosion inhibitinl Properties on the 'comwtion. of the product obtained by the process 1s. A lubricant composition com rising a major amount. suiiloient to conier improved antioxidantand corrosion inhibiting properties on. the composition. or the product obtained by the process amounted a mineral lubricating oil and amino: I

amount. suiiicient to confer improved antioxidant and corrosion inhibitin: properties on the composition. of the product obtained of claim 8.

10. A lubricant composition comprising a major amount 0! amineral-lubrioatin: oil and a minor by the process and corrosion inhibitin:

or claim 7. v v

, 20. A lubricant composition oomprisin: a major amount 01 a mineral lubricating oil and aminor amount, sumoient to confer improved antioxidant not obtained by the process ot'elaim 1i;

.lmnscmmsm'm. morn.cum'rmmn nnrmnncns crrnn The ronowms rcroroncos are or record in the tile of this patent: v

sums rsm'm Number Name Date 2,169,634 Cantrell et a1 M18. 15. 1989 2,409,686 MoNab ct a1. Oct.-22, 1946 2,499,877 May Oct. 22. 1946 2,449,934 Giammaria Sept, 21, 1948 2,456,336 Smith et al.

proper ies. f e pm Dec. 14, 1948 

1. THE PROCESS OF PREPARING AN IMPROVEMENT AGENT FOR MINERAL OIL LUBRICATING WHICH COMPRISES HEATING AN ESSENTIALLY PARAFFINIC BASE LUBRICATING OIL WITH ANHYDROUS ALUMINUM CHLORIDE AT A TEMPERATURE OF FROM 150* TO 300* F., REMOVING ALUMINUM CHLORIDE FROM THE REACTION PRODUCT, AND REACTING SAID PRODUCT AND FROM 5 TO 50 PER CENT BY WEIGHT OF A MONOHYDRIC ALKYLATED PHENOL HAVING AT LEAST 4 CARBON ATOMS IN AN ALKYL GROUP WITH PHOSPHORUS PENTASULFIDE AT AN ELEVATED TEMPERATURE NOT BELOW 300* F. AND NOT IN EXCESS OF THE MINIMUM CRACKING TEMPERATURE OF SAID PRODUCT TO INCORPORATE PHOSPHORUS AND SULFUR THEREIN. 